BOTANICAL INFORMATION. 949 
to the greater volume and rapidity of the Teesta, combined probably 
with its having a shorter course. There can be little difference in the 
nature of the rock or soil over which they flow. 
Some considerable banks of sand lay about, much above the mean 
water-level, deposited by the floods. They contained a large propor- 
tion of the rose-coloured sand, whieh I presume to be the detritus of 
rocks on the higher ranges to the north; for I see no rock likely to 
produce it amongst these hills. 
At eleven A. M. of the 6th, the temperature was 86°; at noon 
90-57, in the forest, and in the coolest shade, by a rill of water, 
89:5^; that of the rill being 72:5?. The black-bulb thermometer 
stood at 123? at eleven a. m., and 140? at noon; the sand was heated 
to 126° and 142? at those hours. These temperatures are by no 
means very high, but, owing to the closeness of the valleys, the heat 
` approached at times to suffocation. Its effect is most sensibly felt at 
ten till noon, by which time so much vapour is raised, as to obscure 
the sun’s direct rays. i 
We followed the same route on our return, and, except finding a good 
many small trees of Ficus elastica, I have little to add. 
(To be continued.) 
BOTANICAL INFORMATION. 
Egor Nut of the Mosquito Shore. 
(Tas. VIL) 
One species of Dipferyr, namely D. odorata, Willd., is an object 
of commerce in its seeds, on account of their fragrance, under the 
name of Tonka or Tonquin Bean: they yield a volatile oil, used largely - : 
by the perfumers and makers of snuff, and which has been ascertained 
to contain a peculiar principle called Cowmarine by the French chemists, 
Stearopténe (Dr. Ure). “The oil is extracted by digestion with 
alcohol, which dissolves the stearopténe, and leaves a fat oil" It has 
a powerful and agreeable odour, as is familiar to most people. Com- 
monly a seed, or ** bean," is put into a box, which yields its fragrance 
to the snuff and lasts for years. i 
Another species of Dipferyz of the Mosquito shore affords a similar — — 
fatty oil, which has long been in vogue with the natives of the Mos- 
VOL. II. 2K 
